The present disclosure relates generally to medical devices. More particularly, it relates to hemodialysis grafts configured for removal of thrombosed regions of the graft.
Hemodialysis includes the use of a dialyzer to clean wastes from blood when a patient's kidneys fail to do so. Also included is a hemodialysis graft, which is connected between an artery and a vein of a patient, preferably in patient's arm. The hemodialysis graft provides a convenient inlet on the artery side for blood requiring dialysis filtration processing, and the outlet is located on the vein side for return of dialysis treated blood from the dialyzer. Regardless of where it is placed, the function of the hemodialysis graft is to facilitate withdrawal of blood from the patient for treatment in a dialyzer and for returning the treated blood to the patient.
Thrombosis, or blood clot formation, is the most common cause of hemodialysis graft failure after a period of time due to stenosis caused by the high rate of blood flow through the graft and repetitive injury at the venous anastomosis. The location of the stenosis is most commonly found at the graft/vein anastomosis, but can also be found along the wall of the graft. A narrowing at this area causes a slow down or obstruction of blood flow, resulting in the formation of the thrombus within the graft. The underlying stenosis, regardless of location, must be corrected in order to avoid recurrence of the thrombus. Typically, patients must have these stenosed regions of the graft widened periodically in order to continue hemodialysis processing through the graft. Furthermore, it is conventional to surgically declot the graft or to install a new graft at a different location. Graft declotting and replacement are surgical procedures, which mean that the patient must undergo repeated surgeries simply to assure blood flow through the graft is adequate to facilitate hemodialysis.
With respect to graft declotting, there are at least three primary interventional radiology methods for percutaneous thrombolysis: Thrombolytic (rolkinase, stereptokinase, Tissue plasminogen activator (TPA, r-TPA), and other) infusion, pulse-spray pharmacomechanical thrombolysis, and pure mechanical thrombolysis. A summary of these various methods can be found in U.S. Pat. No. 7,182,755, which is incorporated herein by reference to its entirety. Despite some advantages, traditional percutaneous thrombolysis often exhibit significant drawbacks. For example, some methods use large devices (8-French or more), which can perform poorly in curved vessels, limiting their use in hemodialysis grafts. Further, residual adherent clot is a considerable problem with some of these methods, and many devices do not remove the macerated clot, which then may be embolized into the lungs.
Thus, what are needed are a hemodialysis graft and a method of use thereof that are configured to minimize graft declotting methods to the implanted graft. It is also desirable to lengthen the period of implantation of the hemodialysis graft, thereby delaying the surgical introduction of replacement grafts.